The present invention relates generally to indwelling catheters and electrode leads and more particularly to introducer systems for introducing catheters and electrode leads into a desired portion of a patient's body.
Catheters and leads are typically placed in a desired location in a patient's body, particularly within the patient's vasculature, by means of introducer systems. These introducer systems typically include an elongated sheath which is inserted into the blood vessel or other portion of the patient's body, through which sheath the catheter or lead is introduced. In those circumstances in which the lead or catheter is to remain in the patient's body for a considerable period of time, it is desirable to be able to remove the introducer sheath without removing the lead or catheter.
One commonly employed mechanism for removing the introducer sheath from around the catheter or electrode lead is to provide the sheath with weakened zones on either side of the sheath, allowing it to be torn or split along weakened zones and removed from the catheter or lead. One introducer system employing this mechanism is illustrated in U.S. Pat. No. 5,409,469 issued to Scheaerf, incorporated herein by reference in its entirety. Another commonly employed mechanism for removing the sheath from around the catheter or lead is to simply slit the sheath along its length as it is pulled proximally along the lead or catheter and out of the patient's body. One such slitter is disclosed in U.S. Pat. No. 4,997,424 issued to Little, also incorporated herein by reference in its entirety.
In many circumstances, it is desirable that a hemostasis valve be provided at the proximal end of the introducer sheath, allowing the introducer to be sealed around the lead or catheter body. The presence of the hemostasis valve, which typically includes a rigid housing containing a compressible seal which engages the circumference of the lead body, poses a problem with regard to removal of the introducer sheath. One approach to this problem is to make the hemostasis valve splittable, along with sheath. An introducer system employing this mechanism is disclosed in U.S. Pat. No. 5,125,904 issued to Lee, also incorporated herein by reference in its entirety. An alternative solution to the problem of providing a hemostasis valve in the context of a splittable sheath is to simply make the hemostasis valve removable from the sheath, so that the sheath thereafter can be split. Introducer systems employing this mechanism are disclosed in U.S. Pat. No. 5,250,033, issued to Evans et al and U.S. Pat. No. 4,473,067 issued to Schiff, both of which are also incorporated herein by reference in their entireties. In the Evans et al patent, a threaded coupling, provided with a pre-weakened zone, engages a removable hemostasis valve. In Schiff, a splittable sheath is simply compressed around the end of a removable hemostasis valve. In both cases, the proximal end of the sheath is not configured to be connectable to standard luer type fittings.